Machine for sharpening of saws



L. LAURENT MACHINE FOR SHARPENING 0F SAWS Aug. 30:

Filed FeB. .5, 1929 3 Sheets-Sheet l on as a aw... m m\\ I V Aug. 30, 1932. L. LAURENT MACHINE FOR SHARPENING OF SAWS Filed Feb. 5, 1929 .Aug. 30, 1932; L. LAURENT IACHINE FOR SHARPENING 0F SAWS Filed Feb. 5. 1929 5 Sheets-Sheet I5 lil Patented Aug. 30, 1932 E TDFEICE LEON LAURENT, or s'r. murmur-Bauer:

I mcnmjma SHARPENING orisaws iApplication filed Februaryv 5, 1929 Serial No. 387,693, a'iigldnlrance February 8, 192 8. a

The present invention relates to machines for sharpening :saws by an artificial grindstone, and is characterized by the utilization of reproducing cams or templates presenting a more or less elongated shape. of theupper part of the tooth to be reproduced, and effecting the raising of the grindstone-support exactly at the moment of the advance of the sawtooth, in such manner, that the grind stone affecting the upper part ofthe tooth to be sharpened, describes during raising, above the tooth a curve determined by the camsection. j u

Different other features will be put forward in the following description referring tothe annexed drawings, which represent diagrammatically inthe way of example, anembodiment of the machine. A

Fig. 1 is a front view of the machine; 7

"Fig. 2 is a lateral view, if looking intthe' direction of the arrows 2-2 of Fig. 1;

Fig. 3 is a plan view of the grindstone-support, the axis of rotation of the grindstone" being removed into the horizontal plan;

Fig.4 is a plan view of apressing device; Fig.5 shows a rider-destined for regulation in accordance with the distance of teeth;

Figs. 6 to 8 refer to detailsy h v r The artificial grindstone 1 is carried, to-

getherwith thedriving pulleys 2, by.. a sup port 3 stirrup-like and pivotingfreely at its extremity3 between'studs or the like 35, 35 around an axis e2 (Fig. 3) paralleltot-he axis of rotationflof the grindstone, in such 1 manner that the latter axis is always displaced parallelly to itself. A V

The studs 35, 35' are supported bya bow 36 which can be fixed in any angular position around the axis 3 y by means of a bolt 37, upon a fixed body .38: Y g g The grindstone-support 3 is provided With a suspension-bracket39 attachedto the lower extremity of a rod 4by means of a double articulation 40,41 forming. a cardan-joint.

This suspension rod 4 is provided at its upper extremity 4' with a threaded spindlefi serving for the regulation'of the lowering of the grindstone' 1.. The lower endof this spindle 5 bears inone of three cups 6, 6 6" of a movable arm 7 pivoting around an axle 8 provided in the frame 9.. I a An extension 1070f this frame supports one or several rollers 11 guiding and supporting a cam-support '12 carryin a reproducing cam 13 of appropriate pro 1e corres onding to the curvature of the tooth to be 0 tained, the cam being fixed, forexample, by means of a screw-14 in avise 15.

For the manufacture of such cams" 13 wood will be found very suitable as it permits the making of said cams by the person using the machine; a few seconds will suflice to replace one cam by another so that the machine will be adapted without groping about, for a novel toothing.

v The arm 7 reposeson the cam-support 12 through the medium of a roller 16. V A lever 17 pivoting around an axle 18 controls simultaneously:' ,At one part, a pusher or tappet provided with a alet 19 and articulated at. 20; its length can 'regu lated by a scerw 19' and itsfunction is to advance-the saw S; At. the other part, the cam-support 12 articulatedat 21 to this lever 17 and the latter is arranged to impart to this support an alternating and essentially rectilinear movement (assumingthat the are described by the extremity21 of the lever is replacedby astraightline. Y q 1' The lever 17 receives its oscillating motion from an oscillating arch 24 through the medium of a connecting rod 22, whose oneextremity 43 is articulated to the lever 17 and the "other extremity 42 to arider 23 adjustablymounted on. the arch 24 for movement lengthwise thereof. The rider has a set screw 24 by means of which the rider may be socured to the arch atany desired .adjustm'ent.

. The arch may be oscillated by any suitable means such as an eccentric or fthe 1ike,;step

pulleys being provided for variation of speed. The bow 24 oscillates around an axis 25 in the direction of the arrow F (Fig. 5) from the position A represented in full lines, up to the position B represented with dotted lines, the lever 17 being thereby oscillated in the direction of the arrow F around its axis18.

The saw blade S (Figs. 1 and 4) is maintained during its advance by a pressing shoe 26 articulated at the end of an arm 27 swinging around a vertical axle 28 (Fig. 4) and applied toward the saw by a spring blade 29, abutting against a stud 30 of the arm 27 and maintained by the wings 31 of a counterplate 32 movable with the spring 29 around an axle 32'. i

The lever 27 with its pressing shoe 26 articulated to the said lever applies itself peri fectly-against the saw notwithstanding its thickness, the flexibility of the spring being regulated by a rider 33 movable in a slide 34 of the counterplate 32. i i

The working of the device is readily to be understood.

The pusher with palets 19, acted upon by the lever 17, advances the tooth of the saw wand the template13 introduces itself below the roller 16 of the pivoting arm 7 at the moment when the upper part of the tooth to be sharpened is situated opposite to the grindstone lwhich describes during its rai s ing, as said before, a curve determined by the section or shape of the template 13. 1

As soonas the advance of the tooth is finished, the tooth is sharpened whereupon the lever 17 moves backwardly and carries with it the template-support 12'and the driver 19;

Thelatter articulated at 20 engages the next tooth u, whilst the grindstone 1, whose supporting bracket 3 oscillates freelybetween the studs 35, 35, descends by its own weight and sharpens the front part t of the tooth, procuring to the same the appropriate cutting angle, the bracket 3, 3 being for this purpose adjustable angularly around the axis e Fig. 6 shows the shape a of the teeth to be obtained and 7 illustrates two sections of the template, 6, breproducing these teeth. v The length of the reproducing cam or template 13 isof course determined according to the differences of strokes of the driver or shifter 19 and of the template-support 12,

these strokes being proportionate to the dis tance separating them from the axle 18 of the lever 17; V

It is possible to obtain with the same template 13 (whose shape is determined in accordance with the shape B y of: the given tooth) all required distances 0 between the teeth. 7' V I The regulation is effected for this purpose by the displacement of a rider (23) along the bow 24 oscillating around its axis 25. 7

In the extreme position B of the bow 24 (see the dotted lines in Fig. 5, corresponding to the end of the sharpening of a tooth), which corresponds to the position viz. the one at the end of the stroke of the template 13, and supposing that the rider 23 is fixed at a point C nearest to the oscillation axis 25, the extremity 42 of the connecting rod 22 coincides owing to the design with this axis 25, in such manner that the backward movement of the lever 17, when considering its movement from the extreme position 17 B in the sense F' is zero, the bow 24 being inactive with regard to the said lever.

If, on the contrary, the rider 23 occupies the extreme position D, the stroke of the lever 17 is the greatest.

Now, the extreme advanced position 17 B is invariable, independently of the regulation of the rider 23, owing to the fact, that if the bow occupies this extreme advanced position B, the center to of the arc of the circle 24 coincides owing to the design with the extremity 43 of the link 22 at the point of its articulation upon the lever 17; hence it follows that the link or connecting rod 22 will be always radial in, this position B, with regard to the are 24, notwithstanding the adjustment of the rider 23, and that this adjustment is without any influence upon the extreme advanced position 17 of the lever 17.

Summing up it will be seen that-the lever 17 is controlled in such manner that its forward stroke (in the sense F) terminates always into the same extreme position 17 whilst an eventual increase of the stroke (in order to vary the distance between the teeth of the saw) is produced at the backward movement (sense F Hence it is possible to obtain the same shape of the tooth, B y, and difierent distances 0 without any displacement whatever of thejtemplate 13. In such case, the action of the support12 upon the roller 16 precedes (and completes) the one of the reproducing template 13. Fig. 8 shows that the action of this support extends itself from a to ,8 and that the action of the template takes place from B to which point is immutable.

It isof course possible to obtain a whole range of intermediate strokes for the lever 17 and hence for the template 13 by the regulation of the position of the rider 23 upon the arc 24, viz. changing the position from C to D.

These different devices permit to employ rationally several working speeds of the lever 17 (for example 30, and strokes in the minute) and hence several advance speeds for the saw S, the duration of sharpening being in each case proportionate to the distance between the teeth; a tooth having the pitch of 3 mm. needs less time for sharpening than a tooth, the pitch of which is equal to 90 mm.

The machine obtained is hence a universal one, sharpeningin a perfectly rational way the teeth with small and great pitches between them and presenting the following advantages:

(a) rapidity and facility of the adjustment for the required distance, the adjustment being eifectable either during stopping or during the working of the machine;

(6) a continuous alternating, oscillating movement of the lever 17; r V

(c) an advance movement terminating always into the same position 17 The grindstone is, as was shown, adjustable with regard to its lowered position, by the screw 5.

Finally, it is possible to obtain b the same template teeth of different dept accord ing as to whether the screw 5 engages the cup 6 or 6' or 6 of the lever 7 whereby the distance of the axle 8 from said screw is modified. Y

The invention is of course not limited to the embodiment shown and described as the same permits very numerous modifications without departing from the general inventional idea.

It is for example possible to obtain an equal result by a fixed reproducing template or the like, upon whichtravels a roller, like 16, acting u on the grindstone-support. Hence it may e stated, in general way, that the template or the like at one part and the means controlling the grindstone at the other part are performing, relatively to each other a rectilinear alternating movement.

Furthermore, the suspension bracket39 can be attached to the bow 3 at any point intermediate between the extremity 35 of this bow and the grindstone 1; in such case, since the grindstone-support is established according to the principle of a lever of the 3rd kind (pivoting at one extremity, application of the force to an intermediate point) the height of the template or the like is established or determined according to the ratio between the arms of levers l35 and 39 -35.

What I- claim, is:

1. In a machine to sharpen the saw-teeth, a controlling lever, means on said lever to advance the saw b" a pitch-after each sharpening, and means to secure an invariable ex treme advanced position of said lever and to increase the eventual backward stroke of the same, a grandstone, a template to raise it, and means to connect said template to said lever, to permit sharpening of saws with equal teeth and different pitches.

2. In a saw sharpening machine, a grindstone, an arm in which said'grindstone is mounted for rotation, said arm being mount ed for universal angular adjustment, supporting means for the free endof said arm, including a vertically movable member for raising and lowering the free end of the arm and hence also the grindstone; an oscillatory lever, a lon itudinally movable cam supporting mem er operated b said lever and on which the weight of sai vertically movable member is'imposed a pivotally mounted lever which bears on the longitudinally movable cam supporting member, an ad usting element with which the vertically movable member is provided and which adjusting element bears and is shiftable longitudinally on said pivotally mounted lever to vary the amplitude of vertical movement of the grindstone without changing the gage or position thereof, a cam on said cam supportin member, and means for moving a sawstep y step for operation upon by the grindstone.

3. A machine for setting the teeth of a saw, including a control lever, means actuated by said lever to feed the saw apredetermined distance after each setting, a grindstone, a cam corresponding with the shape of the saw teeth and the spacing thereof, means connecting said cam with said lever for oper ation thereby, a rocking arc actuating said lever, a runner shiftable on the rocking arc, a rod connecting said lever with said runner and pivotally connected to each of them, the said are when in its most forward position being concentric with the pivotal connection between the rod and the lever, so that the advance stroke of the lever is invariable under all adjustments of the runner to effect variations of the amplitude of movement in the return stroke of the lever.

4. A saw sharpening machine as claimed in claim 2, including a segment member pivotally mounted for rocking movement, an element shiftable on said segment memberand a rod pivotally connected to said shiftable element and also pivotally connected to said lever, the said segment member when in its most forward position being concentric to the pivot by which the rod is connected to the lever, so that the point defining the limit of the forward, feed stroke, of the lever, is invariable at all adjustments of said shiftable element.

In witness whereof I aflix my si nature.

' LEON LA ENT. 

